Device for feeding the cloth in a sewing system for the production of open darts

ABSTRACT

A device for feeding a workpiece cloth which is folded along a fold line along a feed path of a sewing machine, includes a pattern bar, having a guide edge, which is shaped according to the course of the seam, and which defines a guide surface for guiding a flat cutter and the workpiece so that the cutter cuts the workpiece along the folded edge. The pattern bar is mounted for movement to advance the workpiece into association with the sewing machine and the cutter, and the construction includes a stationary guide of U-shaped construction having two leg portions between which the folded end of the workpiece is guided and having a connecting web portion between the leg portions with a cutter access slot into which the cutter projects.

United States Patent [19 Mall [ DEVICE FOR FEEDING THE CLOTH IN A SEWING SYSTEM FOR THE PRODUCTION OF OPEN DARTS [75] Inventor: Gunther Mall, Kaiserslautern, Pfalz,

Germany [73] Assignee: Pfaff Industriemaschinen GmbI-I,

Kaiserslautern/Pfalz, Germany [22] Filed: Jan. 12, 1973 [21] Appl. No.: 322,937

[30] Foreign Application Priority Data Feb. 1, 1972 Germany 7203543[U] [56] References Cited UNITED STATES PATENTS l/l934 Sommer ..ll2/12l.l5 9/1933 Matthews ..83/444 451' May 7, 1974 Primary Examiner-James R. Boler Attorney, Agent, or Firm-McGlew and Tuttle 5 7] ABSTRACT A device for feeding a workpiece cloth which is folded along a fold line along a feed path of a sewing machine, includes a pattern bar, having a guide edge, which is shaped according to the course of the seam, and which defines a guide surface for guiding a flat cutter and the workpiece so that the cutter cuts the workpiece along the folded edge. The pattern bar is mounted for movement to advance the workpiece into association with the sewing machine and the cutter, and the construction includes a stationary guide of U- shaped construction having two leg portions between which the folded end of the workpiece is guided and having a connecting web portion between the leg portions with a cutter access slot into which the cutter projects.

7 Claims, 5 Drawing Figures 1 DEVICE FOR FEEDING THE CLOTH IN A SEWING SYSTEM FOR THE PRODUCTION OF OPEN DARTS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to cloth sewing systems and, in particular, to a new and useful device forfeeding the cloth in a sewing system wherein the cloth workpiece is guided past the sewing machine by a pattern bar which is shaped according to the course of the seam and which is pressed into engagement with the material and moved so as to advance the workpiece material past the stitch forming point of the sewing machine for the production ofopen darts adjacent cut parts of the workpiece.

2. Description of the Prior Art The careful execution of the process of producing darts contributes to the good appearance and the good fit of the garments which are made. The procedure which is followed in making darts is as follows: The cut part is folded over the folding bar and transferred to a feed bar. The feed bar is then placed over the folded cut part leaving the seam region free and it guides the folded material past the stitch forming point of the sewing machine. In the mechanical production of open darts, the double layered material of the dart fold is trimmed at a spaced location from the seam by means of an edge trimming cutter or knife which is also carried by the sewing machine equipment adjacent the sewing machine. If the cloth layers of the dart are to be cut open close to the point of the dart in order to avoid bulkiness in the region of the point, the cloth layers of the dart must be trimmed very close to the seam. However, if this is done, the remaining free cloth edges become very narrow and thus they may fray very easily. In addition, the flat ironing of the narrow cloth edges presents difficulties. The flat ironed cloth edges in garments of very thin materials and those which are intimately joined on the inner side with a fusible lining to reinforce the front parts are visible on the finished garment close to the dart seam.

In order to avoid the above disadvantages, the clothlayers of the dart must be cut open by hand after the formation of the seam along the folding edge. If time consuming cutting by hand is to be eliminated, the distance between the blades for trimming the edges and the seam must be increased and such blades generally move upwardly and downwardly in a vertical plane. The wider the cloth edges which are selected, however, the greater is the zone in the range of the dart point, particularly in very acute angled darts, which is not cut open and which either comes to lie only on one side of the seam during the ironing, or which is ironed flat symmetrically to the seam lining like a cone. Due to this accumulation of material, the dart bulges considerably on the finished garment and this is particularly conspicuous in the end region of the dart point.

SUMMARY OF THE INVENTION In order to avoid the above disadvantages, the invention provides a system in which both layers of the dart which embraces the sewing material over the folded edge. The guide includes an oblong slot for the entrance of a cutting tool whose cutting edge protrudes between the cloth layers of the dart fold.

According to another feature of the'invention, which ensures a particularly simple and expedient execution, the cutting tool is arranged with its drive on a bearing lever which can turn about an axis extending perpendicular to the displacement plane of the sewing material. In order to control the course of the cut in dependence on the form of the dart, the bearing lever bears tensionally on the pattern bar determining the form of the seam. In order to be able to adapt the course of the cut to differently shaped darts and different materials, the bearing lever is equipped with a movable part which carries a supporting roller bearing on the pattern bar. A particularly suitable cutting tool for cutting the dart fold along the folding edge is a polygonal flat blade which is located at a relatively small distance above the bearing surface for the sewing material and which r0- tates in a plane parallel to the supporting surface of the sewing material or workpiece.

Accordingly, it is an object of the invention to provide an improved device for operating on a folded workpiece cloth which is folded along a fold line and which includes means for advancing the folded workpiece into association with an operating sewing machine needle and for presenting the folded edge through a U-shaped stationary guide having a slot into which a' rotatable cutter is arranged, and wherein the cutter cuts the workpiece along the fold line as the workpiece is guided past the stitching needle.

A further object of the invention is to provide a device for feeding a folded workpiece cloth on a sewing system which includes afeed barwhich has an upstanding guide edge and a flat pressing plate edge .which engages with the workpiece and which is advanced by a carriage to present the workpiece into association with a stitching needle and which includes a guide edge for guiding a cutter and the material when the material is moved past the stitching needle and 'which also includes a fixed guide which embraces the material along the folded edge and which is provided with a slot into which the cutter projects for cutting the material along the folded edge.

A further object of the invention is to provide a simplified sewing system which is simple in design, rugged in construction, and economical to manufacture.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is a front elevational view of a sewing system constructed in accordance with the invention;

FIG. 2 is a section taken along the lines 11-11 of FIG. 1;

FIG. 3 is a section taken along the lines III-III of FIG. 2;

FIG. 4 is an enlarged partial perspective view of the cutting tool and the workpiece guide shown partly broken away and partly in section; and

FIG. 5 is a partial perspective view of a dart after flat ironing and produced with the device constructed in accordance with the invention. I

. double chain stitches.

GENERAL DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein comprises, a sewing system which includes a frame 1, having a table top 2 defining a top surface for supporting the surface of the workpiece for feeding therealong. A sewing machine 3 is arranged along the feed path overlying the table top 2 and it includes a head 4 which is mounted in a known manner vice'but the feeding means for the workpiece is incorporated in the sewing system. For this purpose, two parallel guide bars 9 and 10 are mounted in laterally spaced relationship on the frame 1 and a carriage 13 is movable therealong under the drive of a motor 11 which rotates a drive sprocket 11a to move a chain 12 which is secured to the carriage 13. The chain is guided over a return sprocket 11b. The carriage 13 includes a carrier part 16 which extends longitudinally and which is guided in the manner of a cross-slide which is movable along the spaced transverse guide bars 14 and 15.

U-shaped arms 17 and 18 are secured to the respective ends of the carrier 16 and they extend vertically upwardly on one side, the sewing machine side, of the table 2. The U-shaped arms 17 and 18 include. sides of unequal length and the short sides of the arms 17 and 18 are connected to the carrier 16 while the long sides extend above the table top 2 parallel to the longitudinal axis of the sewing machine 3. The free ends of the long or upper sides of the arms 17 and 18 carry compressed air motors 19 and 20, respectively. The compressed air motors l9 and 20 include piston rods 21 and 22 which are vertically movable and which are connected to a Support means are provided for adjustably supporting a rotatable cutter or polygonal blade so that the blade passes into the slot 34 and protrudes between the layers of the folded cloth so that it is out along the fold line. The support means include a cutter shaft 36 which is supported on a pivotal cutter support arm or lever 38 along with its drive motor .37. The cutter 35 may comprise a polygonal or circular blade for cutting the dart fold along the folding edge or a pivotal cutting tool which oscillates about a vertical axis may be employed which has a cutting edge in the form of a blade which protrudes between the cloth layers of the dart folds. The bearing lever 38 advantageously comprisesa single piece but it also carries a movable lever part which carries a supporting roller 39 which bears against the guide ledge 25 of the pattern bar 23. The movable lever part 40 and the bearing lever 38 are braced together by means of a screw bolt 42 which passes through an oblong slot 41 in the movable part 40 and also through the free end of the bearing lever 38. This construction permits a variation of the distance between the supporting roller 39 and the polygonal blade 35 which is pattern bar, generally designated 23. The pattern bar corresponding to the desired seam line S and the form of the dart.

The forward end of the sewing machine 3 carries a vertical support bar 26 which includes a cross-plate 27 at its lower end having laterally spaced vertically arranged roller shafts 28 and 29 which carry rollers 30 and 31 which rotate about vertical axes on respective sides of the guide ledge 25 and bear against the guide ledge.

In order to be able to cut the double-layered cloth of the dart along the folded edge of the workpiece W, the invention provides a U-shaped guide 32, which is fastened to the cloth supporting plate of the sewing machine by means of a screw 33, which includes top and bottom leg portions 32a and 32b which are connected by an end web portion 32c as shown in FIG. 41. The leg portions 320 and 32b engage on respective sides of the workpiece W which is fed with its folded end adjacent the web portion 320 so that it passes alongside an elongated slot 34 of the guide 32.

carried on the driving shaft 36 of the motor 37. This also makes it possible, therefore, to vary the depth of penetration of the cutting tool in respect to the folded edge of the workpiece W.

The bearing lever 38 is mounted for rotation about a stationary stay bolt 43 as shown in FIGS. 2 and 3. A two-armed combination torsion spring and compression spring 44 surrounding the stay bolt 43 urges the bearing lever 38 into engagement with an adjusting ring 45 which is secured on the upper ,end of the stay bolt 43, as shown in FIG. 3. The combination torsion spring and compression spring 44 includes an arm portion 46 which is anchored in position on the cloth supporting plate of the sewing machine 3, and an opposite arm portion 47 which bears against the bearing lever 38 and urges it in a direction to cause engagement of the roller 39 against the guide ledge 25 of the pattern bar 23. A stop pin 48 is arranged in the path of movement of the lever 38 and it limits the maximum rotary movement of the lever when the pattern bar 23 is withdrawn. A parallel carrier (not shown) may be also employed for supporting the rotary cutter 35 and its drive motor in a position at which the cutting edge thereof will be accurately positioned in respect to the workpiece W.

The compressed air motors 19 and 20 are connected through flexible hose lines 49 and 50, as shown in FlG. l, to a compressed air source (not shown) and they are controlled preferably by electromagnetic valves (not shown). The control of the valves as well as the sewing machine motor 7 and the feed motor 1 I and the cutter motor 37 can be effected either by hand or by an automatic control.

The device of the invention operates as follows:

The workpiece W, which is to be provided with darts, for example, the front part of a jacket, is folded at the point provided for the dart and, as a rule, is provided with an indication mark and aligned under the pressure ledge 24 of the pattern bar 23 which is first lifted by the action of the compressed air motors l9 and 20. The pattern bar 23 is subsequently lowered to cause the pressure ledge 24 to engage over the workpiece W at a location to leave a width necessary for the seam. The workpiece W is thus engaged frictionally by the pressure ledge 24. By actuating corresponding switches, the motors 7, l1 and 37 are then started. The motor 7 drives the sewing machine through the belt 8 while the motor 37 starts the polygonal blade 35 which is secured on the shaft 36. The motor 11 displaces the carriage 13 with the carrier 16 and thus the feed bar 23 which is carried on the arms 17 and 18. The feed bar then advances the workpiece W from the starting position indicated in FIG. 2 in a direction of the arrow D, shown in FIGS. 2 and 4.

During displacement of the workpiece, the dart seam form is determined by the configuration of the guide ledge 25 which passes between the guide rollers and 31 which are arranged on the sewing system. The seam which is formed is indicated by the broken line designated S in FIG. 2. By a corresponding control of the motor 11, the seam can be locked from the start to the end by closer stitches or by making the stitches with a brief reversal of the direction of feed.

During the displacement, the dart is conducted into the U-shaped guide 32 arranged behind the stitch forming point and passes the slot 34 and the polygonal blade 35. The blade protrudes through the slot 34 between the cloth layers of the dart fold, as seen particularly in FIG. 4. The dart fold is thus cut open during the sewing along the folding edge.

During the cutting, the cloth layers of the dart fold are supported by the guide 32 from both sides and can therefore not yield. The use of a polygonal blade as a cutting tool ensures a satisfactory execution of the cut even with relatively thin materials. The depth of penetration C, as shwon in FIG. 2, of the cutting tool working between the cloth layers of the dart fold can be adjusted by varying the position of the movable part 40 on the bearing lever 38. A zone a of the workpiece, which is not cut open in order to ensure the durability of the seam, will be of a length which depends upon the penetration of the blade 35.

Due to the tensional bearing of the supporting roller 39 of the bearing lever 38 on the guide ledge 25 of the pattern bar, an accurate control of the course of the cut is ensured. After the seam line along the line S has been completed during the displacement of the feed bar 23 with the workpiece W from the right to the left, as shown in FIG. 2, and the dart fold line has been cut open along the folding edge with the exception of the zone a, the motors 7, 11 and 37 are shutoff by a limit switch, for example, (not shown) which may be located on the frame 1 in the path of the carriage 16 or the carriage 13 and it may be connected to the chain 12 at the end of the displacement path of the feed bar 23. The feed bar 23 is lifted from the workpiece W by a supply of compressed air to the motors l9 and 20 and the workpiece is'then removed. The feed bar 23 may be brought back to the starting position, shown in FIGS. 1 and 2, by starting the motor 11, and a new workpiece is then placed under the pressure ledge 24 and the process is repeated.

In case the feed bar 23 must be removed from the machine for some reason, for example in order to replace a pattern bar 23 with a different form of guide ledge 25, the stop pin 48 limits the rotary movement of the spring-loaded bearing lever 38.

A dart made with a device according to the invention is shown in FIG. 5 in a condition after ironing. A very short zone a, which is not cut open, is located adjacent the dart point. The free cloth edges of the open dart fold are relatively wide and they can be easily separated from each other for ironing.

The flat ironing of the uncut part of the dart is substantially facilitated by the easy handling of the wide edges because the uncut part in the zone a of the dart is already 'preshaped during the flat ironing of the free edges.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A device for forming darts on a seing system using a sewing machine, comprising means defining a feed path along which the folded workpiece cloth is fed, a sewing machine located along the feed path, a feed bar having an upstanding guide ledge and a flat pressing plate portion engageable with the workpiece, means for moving the feed bar with the workpiece along the feed path to move the workpiece into engagement with the sewing machine for sewing a seam therealong, cutter means adjacent said feed path for cutting the workpiece along the fold line, and a U-shaped guide member having two leg portions between which the folded end of the workpiece is guided and having a connecting web between the leg portions with cutter access slot into which the cutter projects for cutting along the fold edge and between the folded layers of the workpiece.

2. A device for forming darts on a sewing system, ac-

cording to claim 1, wherein said cutter means includes a pivotal bearing lever, means mounting said bearing lever for pivotal movement substantially perpendicular 'to the displacement plane of the workpiece, a cutter rotatably supported on said bearing lever, said bearing lever having a guide part engaged with said guide edge for controlling the position of said cutter relative to the workpiece and which is movable with the configuration of the guide ledge to move said bearing lever with said cutter toward and away from the workpiece.

3. A device for forming darts on a sewing system, according to claim 2, wherein said guide part of said bearing lever comprises a member mounted on said bearing lever and being adjustably displaceable in respect theretoand having a roller thereon engaged with said guide ledge, said guide part being adjustable in respect to said bearing lever in order to vary the spacing of said knife in respect to the workpiece.

4. A device for forming darts on a sewing system, according to claim 1, wherein said cutter means comprises a rotatable polygonal blade.

5. A device for forming darts on a sewing system, ac-

' cording to claim 1, including means connected to said feed bar for moving said feed bar upwardly and downwardly in respect to said feed path in order to effect engagement and disengagement of said pressing plate portion with the workpiece.

6. A device for producing open darts comprising a' table defining a support surface over which a workpiece is fed, a pressing and feed bar having an upstanding guide edge and a flat pressing plate portion engageable with the workpiece, a carriage carrying said pressing and feed bar and having means for moving said pressing and feed bar toward and away from the workpiece to effect engagement and disengagement of the workpiece, means connected to said carriage for moving said carriage to advance the feed bar with the workpiece along the table, a sewing machine located along said table in a position to operate on the workpiece as it is fed along said table, a bearing lever pivotally mounted adjacent one end alongside said table, a rotatable cutter carried on said bearing lever, means for biasing said bearing lever in a direction to position said cutter in engagement with the workpiece on the table, a U-shaped guide member located adjacent said table and having two leg portions between which the folded end of a workpiece is guided and having a connecting a web portion between the leeg portions with a cutter access slot into which said cutter projects, and guide ing in respect to said bearing lever. 

1. A device for forming darts on a seing system using a sewing machine, comprising means defining a feed path along which the folded workpiece cloth is fed, a sewing machine located along the feed path, a feed bar having an upstanding guide ledge and a flat pressing plate portion engageable with the workpiece, means for moving the feed bar with the workpiece along the feed path to move the workpiece into engagement with the sewing machine for sewing a seam therealong, cutter means adjacent said feed path for cutting the workpiece along the fold line, and a U-shaped guide member having two leg portions between which the folded end of the workpiece is guided and having a connecting web between the leg portions with cutter access slot into which the cutter projects for cutting along the fold edge and between the folded layers of the workpiece.
 2. A device for forming darts on a sewing system, according to claim 1, wherein said cutter means includes a pivotal bEaring lever, means mounting said bearing lever for pivotal movement substantially perpendicular to the displacement plane of the workpiece, a cutter rotatably supported on said bearing lever, said bearing lever having a guide part engaged with said guide edge for controlling the position of said cutter relative to the workpiece and which is movable with the configuration of the guide ledge to move said bearing lever with said cutter toward and away from the workpiece.
 3. A device for forming darts on a sewing system, according to claim 2, wherein said guide part of said bearing lever comprises a member mounted on said bearing lever and being adjustably displaceable in respect thereto and having a roller thereon engaged with said guide ledge, said guide part being adjustable in respect to said bearing lever in order to vary the spacing of said knife in respect to the workpiece.
 4. A device for forming darts on a sewing system, according to claim 1, wherein said cutter means comprises a rotatable polygonal blade.
 5. A device for forming darts on a sewing system, according to claim 1, including means connected to said feed bar for moving said feed bar upwardly and downwardly in respect to said feed path in order to effect engagement and disengagement of said pressing plate portion with the workpiece.
 6. A device for producing open darts comprising a table defining a support surface over which a workpiece is fed, a pressing and feed bar having an upstanding guide edge and a flat pressing plate portion engageable with the workpiece, a carriage carrying said pressing and feed bar and having means for moving said pressing and feed bar toward and away from the workpiece to effect engagement and disengagement of the workpiece, means connected to said carriage for moving said carriage to advance the feed bar with the workpiece along the table, a sewing machine located along said table in a position to operate on the workpiece as it is fed along said table, a bearing lever pivotally mounted adjacent one end alongside said table, a rotatable cutter carried on said bearing lever, means for biasing said bearing lever in a direction to position said cutter in engagement with the workpiece on the table, a U-shaped guide member located adjacent said table and having two leg portions between which the folded end of a workpiece is guided and having a connecting web portion between the leeg portions with a cutter access slot into which said cutter projects, and guide means carried on said bearing lever and engaged with said guide edge for guiding said cutter in respect to the workpiece in accordance with the configuration of said edge.
 7. A device for producing open darts, according to claim 6, wherein said guide means comprises a plate having a roller thereon engaged with said guide edge and means mounting said plate for adjustable positioning in respect to said bearing lever. 